Cherry blossoms reach their peak in Washington

(CNN) — It's a Washington tradition that isn't subject to partisan bickering or a lobbyist's best efforts to influence.

The blooming of the US capital's cherry blossoms reached its peak on April 5, two days later than the average peak bloom date.

Peak bloom is defined as the day when 70% of the Yoshino variety blossoms are open on the cherry trees surrounding the Tidal Basin.

"Best viewing of the trees will be for the next four to seven days, but they can last for up to two weeks under ideal conditions, such as cool temperatures to slow the progress from flowers to leaves, and a lack of high winds or heavy rains to bring the petals down," National Park Service spokesman Mike Litterst said in a statement.

Initial predictions were for an early peak this year, but cooler than expected temperatures pushed it back.

The blossoms usually peak between the last week of March and the first week of April, but the park service reports that warmer or cooler temperatures have led to earlier blooms (March 15, 1990) and later blooms (April 18, 1958).

A gift of 3,000 trees

The festival commemorates the 1912 gift from Tokyo of 3,020 cherry trees to Washington.

The first trees actually arrived two years earlier, a gift from the city of Tokyo and due in part to the advocacy of Eliza Ruhamah Scidmore, one of National Geographic Society's first female board members.

These trees turned out to be diseased and were destroyed. In 1912, first lady Helen Herron Taft planted one of the first of more than 3,000 replacement trees sent from Japan.

The 1912 gift of trees included 12 varieties, but now two varieties -- the Yoshino and Kwanzan -- dominate.

More than 20 years later, civic groups and local government came together in 1935 to hold the first official festival.

The pink blossoms of the Kwanzan trees are often found in the East Potomac Park area, while the white blossoms of the Yoshino are found closer to the northern part of the Tidal Basin near the Washington Monument.